Jetaway

5thhorseman and Powderkeg, Thank you both. Rebuilding the cylinders seems like an excellent idea. I might just go ahead and replace both drums because even the better one was a marginal call as to usefulness. I'll see if I can scare up a micrometer and check the yards, might just get lucky on this. The originals were aluminum? You sure? I think mine are cast iron or otherwise ferrous. A magnet stuck to the fins and I assume that they wouldn't be cast iron on the outside and aluminum on the inside. Other way, maybe. Chris

I have a 1972 and Chilton's indicates the same setup, so assuming they are the same and I've got them hooked up correctly: Using Pat Carr's photo going from left to right: The left-most and smallest (partially hidden) connects about 1/3rd of the way up the evaporation canister and hooks up to the tank on the passenger side, maybe midway up. You have to get under the car to even see this one. The second (medium) goes to the driver's side, top of the tank. The third (large) goes to the passenger side, top of the tank. The last and largest loops back to the filler tube. Can't guarantee the bolt size, but I just fit a M6 Pitch 1.0 lock washer on mine as a test. Seemed to fit tightly. Chris

I have a 1972 and Chilton's indicates the same setup, so assuming they are the same and I've got them hooked up correctly: Using Pat Carr's photo going from left to right: The left-most and smallest (partially hidden) connects about 1/3rd of the way up the evaporation canister and hooks up to the tank on the passenger side, maybe midway up. You have to get under the car to even see this one. The second (medium) goes to the driver's side, top of the tank. The third (large) goes to the passenger side, top of the tank. The last and largest loops back to the filler tube. Can't guarantee the bolt size, but I just fit a M6 Pitch 1.0 lock washer on mine as a test. Seemed to fit tightly. Chris

Sorry if this is real basic stuff, but I simply don't know. Vehicle: 1972 240Z I recently pulled the rear drums to check the brake linings. Not quite gone, but getting close enough to replace. While I had the drums off, I checked the inside diameter of the drum with a ruler (no micrometer). Both drums had a ridge of sorts around, I guess the inside (towards differential) interior. I'm guessing that the ridge was the part of the drum that did not come into contact with the brake shoes. Measuring across the ridge, one of the drums, even using such a crude device as a ruler, clearly exceeded the maximum stamped on the drum (10.06 inches, I believe). The other -- well, simply couldn't tell using a ruler. Several questions: Would I gain a few months of use simply by replacing the shoes? Assuming one of the drums can be resurfaced and replacing the other with a new one -- is this a good idea? Or given that one drum would be new and the other near the end of its useful life, would the difference in stopping power be so great as to be annoying or even dangerous? Should I replace the wheel cylinders even if they are currently working? Finally, more of an opinion type question: I looked up prices for components at the Z-Store (not always the cheapest but not always the dearest either) and figured it would run me roughly $200 to replace both drums and approaching $400 to replace both brake cylinders as well. I don't know if the brake cylinders have worn out, but given that I suspect they've given 39 years of service, I'm guessing it wouldn't be a bad idea. The Z-store sells a disc brake replacement kit for early Z's for $350.00 (w/o rotors and calipers) and also has a kit that includes rotors and calipers for $770.00 . I don't drive competitively (at least not competitively as in numbers on the side of the car;)) but I do drive my Z between 15,000 and 20,000 miles a year. I'm pretty easy on brakes, viewing using the brakes as a sign of failure on my part to anticipate traffic flow (went 150,000 from new in my Pontiac Aztek before replacement and could have gone further, but tired of having them checked). When in the mountains / foothills I have enough sense to downshift on long downgrades. So, the main advantage that discs have over drums, resistance to fade, isn't really a concern for me. Still, I'd imagine going to 4-wheel discs might stop me a few feet shorter in an all-out sweaty palms WTF! stop which is worth a few bucks. The other concern with _not_ converting is how much longer the original parts will be available for the Z. Thoughts? Oh -- I prefer to keep the car as original as possible, though with an electronic ignition and ZX 5-spd, "Iron Cross" wheels and gas tank filler lid from a '71 just because I like the look of the latch, "Smiling Jack" isn't going to win any concours. All in all, though, my preference is towards the original. Chris

In a word, yes. I was very busy with work when I bought my Z and a student (college) whose family built race engines (American, not a Z's) offered to adjust the valves for $30. I said, OK as he could do it while I was at school. Clattered all the way home. I parked the Z for a couple of weeks and when I did adjust the valves it had a lot more power. Do I know for an absolute fact that tight intake valves cause low vacuum? Nope. But they could. You shouldn't think just in terms of the absolute measure -- .001 or .002, but in terms of percent. Your intakes are 1/8th or 12.5% tight and the exhaust somewhere between 20% and 25% loose. Bit more ominous, isn't it? Your engine may have other problems but until you get the valves adjusted correctly, your diagnostics are as likely to lead you down a blind alley as solve any problems. Chris Chris

For a cold engine your intakes tends towards a little tight and exhausts loose. Clearances should be: Cold: Intake .008 Exhaust .010 Hot: Intake .010 Exhaust .012 Every manual that I've read that makes note of the difference between cold and hot strongly suggests adjusting the valves only when the engine is hot. In an ideal world, the only time you adjust valves cold is after a rebuild. And then after getting the engine installed and running, adjust them again while hot. You seem willing to put in the time so I'd suggest doing them twice. Once, cold to get them close (and for practice) and then after driving around for at least 15, preferably 30 minutes, do'em again while hot. The tight intake valves could lower your vacuum as they are effectively being held open to long and the compression stroke could be pushing the charge back into the intake manifold. The exhaust valves, I'm almost willing to bet, is the cause of your lousy gas mileage. They are not opening deep enough or long enough to allow the burnt gases to escape. Your injectors are sending in the gas expecting it to burn with X amount of air but effectively you only have X-Y, where Y is the volume of burnt gases, of air to combust. Since you have a manual, you don't have to bother with giant sockets or remote starters. Just put it 5th and push. If that's a little too difficult, loosen a few plugs (mark the wires first, please!) and you could push it to Kansas. Don't sweat it. You far more ambitious than I have been and about the worst that can happen is getting a nasty cut/bruise on a finger when loosening a nut. Just be sure to write down which one's you've done and tighten the, whatever the hell the bigger nut is called, the securing nut will do, back after turning the other nut to adjust the clearances and you'll be fine. Chris

Greetings, Not exactly sure where this should go, but here goes. While out hunting for a turn signal switch for my 1972 240Z (see my post under Parts Swaps) at the Stockton, California Pick 'n Pull I came across the following vehicles / parts which may be of interest. 1971? 240Z (for sure). Pretty thrashed out, had the E48? intake manifold I posted about under Carbs. Sheet metal not bad on left, but cut up, literally cut up on right side. Very odd. Hood in good shape, seats possible, though they can't appreciate being under a bunch of parts from misc. cars. 1981 280ZX 2+2: Close to complete. 1976 280Z 2+2: Appears to be an abandoned project car. I'm not an expert at this, but the body sure appeared ready for priming to me. Taken down to bare metal, some red filler type stuff here and there, also sanded down. All body parts present. Had all windows except driver door and that may well have been inside the car. Dash beat up, but headliner, rear panels in excellent condition. Think the engine was missing. Yes, I know what an engine looks like, but I didn't write it down and remember thinking what a great car for a transplant. 1981 280ZX: Pretty complete actually, hood was in great shape. What attracted my attention was it had a turbo with the exhaust manifold and downpipes attached. It also had part of the intake, not the intake manifold itself, but part of the plumbing which bolted directly onto the turbo. The turbo and the rest had been detached from the engine (which was present, but no heads). As a guess, and I don't know why, it looks like someone needed every thing between the block and the turbo and left the rest. Bees -- Damn, there was a big swarm of them suckers hanging near the Nissan area. Could well have contributed to my possible E46 / E48 confusion. Chris

Folks, While digging around the junkyard today I came across what I wrote down as an E48 intake manifold. It was inside a 1971? 240Z (for sure) along with parts obviously not from any 240 -- 280 Z through ZX and others that may have been from a Z. It was a Nissan, dual carb, for a six-cylinder. Compared with the E88 on my 1972 it was very sparse, as a descriptor, I guess. Had a balance tube but I don't think it had a provision for coolant pass through. The runners were also more "tube-like" than on the E88. I couldn't find a reference to it here, though there were discussions of an E46 manifold. Was this an E46 that I just wrote down wrong? If not, is it for a Z? Finally, whether an E46 or an E48, would it offer better breathing than the E88 I currently have installed? Chris

Greetings, I tried to clean up the turn signal switch in my 1972 240Z and while successfully cleaning the contacts, managed to break the circuit board when installing it back into the metal case. Le Bummer. Went to the local junkyard and struck out with the Z's. However, on my way out I happened upon a 1976 Datsun pickup (model unknown). I took a look and, damn, the turn signal switch sure looked like the one I was looking for. As it turned out nearly identical. Physically it is exactly the same. One difference is that it uses all six pins in the connector instead of five. The sixth is used by the horn ring which is separate on the Z. I did have to swap a couple of pins in the connector to get left left and right right and, frankly, that may have been due to a P.O's earlier efforts. On the pickup it mounts under the steering column and because of this the wires come off in the opposite direction as they do on the Z switch. Didn't seem to cause any clearance problems when mounted. Chris

Shot in the dark here. In 240Zs the tachometer forms an electrical loop in the ignition system and if not plugged in, regardless of whether the tach functions or not, the engine will not run. If the 260Zs have the same set-up and assuming that the PO was somewhat responsible for bollixing up the electrics then ... The PO, by chance or design, created an ignition loop that bypassed the tachometer altogether. Then you came along and by cleaning up the wiring inadvertently changed this ad hoc loop such that the previously electrically dead tach wires now produce a short to ground. I'll admit the three devices you mentioned as working in a follow-up post don't seem like likely candidates for the ad hoc loop, though POs can be awfully creative at times. If I had to choose the most likely candidate, it would be the ammeter. Did you work on the ammeter but not include it in your "i.e.?" Chris

And dooohh! I meant to add that I doubt there is anything special about the MG Chemical cleaner and any brand should do. The advantage to getting a cleaner with lubricant is that it is much kinder to switches and such, and your Z likely has a few that wouldn't mind a cleaning. Chris

Definitely replace the O-ring. More than likely available at a local dealer and shock, shock, you'll even get change back from a ten-spot. If it still leaks, it could be leaking through one of the electrical connections. I must have wrestled so hard with one of the connectors when I removed the sender a year ago that I managed to break the connector free enough to rotate, and as a result leak gas. At most I could put eight gallons in before it would start leaking. To fix it I used JB Water Weld (not the liquid stuff, a 2-part putty) packed into every possible crevice in the connector. One of the connectors is part of the case (ground, I would think) and can't leak, you want to work on the other one. JB claims it cures even while submerged in gasoline and I don't doubt them, but I let it air-harden for a day before reinstalling the sending unit. While you are there, might as well clean the sending unit. I didn't trust my "touch" enough to avoid breaking the resistor wire so I used a spray electrical contact cleaner. I believe it was a cleaner from MG Chemicals. I used the cleaner with lubricant, which at various times is labeled as having 'lubricant' and other times not, but with the magic words "with poly ethers," and sometimes labeled with both. (I'm not at home, but I'm pretty sure about the brand and the magic words -- or at least pretty close.) Chris

I recall reading, relatively recently, in an early 1970s Road and Track during the great unleaded fuel change over that it turned out not to be a big deal. Basically, engines that needed lead for the valve train could run without harm on unleaded fuel because the lead in only a few tanks was sufficient to protect the engine for life. Pretty sure, in fact, that GM concluded that one tank of leaded was sufficient. I doubt they contemplated 40 year old engines with 250K+ miles on them when making this conclusion, but the mechanism by which it worked was similar to that described by 5thhorsemann and its possible that once part of the metal, it doesn't come off easily, so whether they were thinking 10 years and 100K or 40 years and a quarter million it doesn't matter much. Chris

In Feb. 2010 I posted a thanks for the tip on the KIA weatherstripping and added this bit. Another poster asked if I was worried about moisture being absorbed by the foam. I hadn't thought of that, told him that I'd keep my eye on it. One year and with a rainy season almost in the books, I can say: to myself; at least one year and to the inquiry; Ah, no worries. Link to original: http://www.classiczcars.com/forums/showthread.php?t=37308&page=2 Chris

I'm going back to the original post where Mr. Cheese described the car overheating, cooling off a bit, but then dying a quarter mile from home. He tried starting it at that time and it didn't start. I'm thinking the overheating has something to do with no spark, but what? The overheating could have taken out the coil, I guess, but that's been replaced. In fact, I think most, if not all, of the usual suspects have been rounded up to no avail. Could the overheating fried some insulation someplace in the ignition circuit? Or expanded metal one too many times and created a loose connection? Or, maybe the overheating and no starting is a coincidence. One of the bonuses of having a 30+ year car. Chris

Greetings, Background: Inspiration: A couple of weeks ago I posted a plea for help in the Engine & Drivetrains forum under "Plug Reads?" Much help was given and since then I have replaced the plugs, wires, distributor cap and rotor. Running much smoother since then. But because a big part of my troubles was due, I think, to the plug wires wearing out, not because of age, but because of physical handling, I wondered if there was an inexpensive, non-destructive way of getting a handle on the health of my ignition system. Which leads to: Knowledge of Oscilloscopes: While not 100% accurate, my knowledge concerning the use of oscilloscopes is well approximated by Sgt. Schultz of Hogan's Heros fame: "I know nothing, nothing!" I mean, I know they plot voltage (vertical) against time (horizontal), that the scale is adjustable by turning knobs and that each square of the grid represents the voltage and time displayed on the bottom of the screen. Beyond that, not much beyond the on/off button seems to turn it on and off. The scope is a Tektronix 2465 that I picked up at a garage sale for between $35 and $50 a few years ago. It has not been calibrated or indeed has had any sort of servicing done since I bought it. It does, however, appear accurate in the time dimension when tested with an audio generator. I tested voltage with a D-cell (new and tested with a multimeter) and the voltage, at least up to 1.6 volts, is correct. The pickup I'm using for these traces is an open reel head made by no idea and of unknown vintage. As a guess -- cheap and mid 1960s. It is held in place on the plug wires with a small C-clamp, which now that I think of it, may be a perfectly serviceable inductor in it's own right. The Car: 1972 240Z, but has an early ZX distributor (E12-80 ignitor model) which has been further modified by replacing the dying E12-80 with a GM HEI style ignitor. A cheap one at that, cheapest Carquest model at the time. Replaced the existing Nissan coil with an Accel coil, mainly because Nissan's coil - terminal was physically decaying. That and yellow is such a groovy color. Questions: General: The big one is am I simply wasting my time with this oscilloscope? The traces I've gotten aren't anything like the neat, precise lines I've seen on this site and in references from here to outside resources. I'm guessing (see Knowledge of Oscilloscopes above) that part of the problem is that newer, digital scopes can separate the display from the measurement units in a way that an old analog scope cannot. If the scope is indeed useful, am I out of my mind using a tape deck head as an inductor? Specific: I've attached 3 pictures taken of the scope's screen. In the lower right hand corner of the scope I labeled which wire was being tested. C= Distributor to coil wire and the other two should be self-explanatory. I would have taken more, but the pictures got worse, that is, only the 'flash' could be seen as the sun continued moving to the west. Memo to self: Start earlier in the day. I know that the voltages won't mean a thing by themselves without calibration (not going to happen) and consistent positioning (working on it), but I am hoping that a comparison between wires will be of use at spotting potential misfires. Tried to keep the engine at 1000 rpm, but it does drift a bit. Preface all statements with: I think, as far as I know, etc. The trace Z...-2 is of the distributor to coil wire. I'm pretty sure that what is seen is two firings of the ignition coil. The oscillations after the peak voltage are normal, as is upside down U right before the peak voltage. I'm puzzled by two things: The first is the difference between the peak voltages. Looks to be about 1 and 1/2 grids, or 30% to 40%. The second is the secondary peak between the peak fires. I'm pretty sure that its not an artifact of the photo, as I saw it consistently, and, looking at Z...-14 which is a trace from the distributor to the #1 cylinder shows a similar secondary peak. Z...-14 also brings up another puzzler, with the measured voltage about 4 times as large as the coil to distributor's voltage. Could be inconsistent placement of the pickup, though it still seems large. OTOH, the overall shape and timing of deviations from zero appear very similar to the coil / dizz trace. I deleted one attachment and substituted a second of the distributor to coil trace. It's not a close-up of a fire, rather it was taken with scope taking twice as many measures per unit of time (twice the speed? Half the speed? Don't know the vernacular) than in the first picture. Whatever, it more clearly shows the mysterious (to me, at least) secondary peak. Any comments, interpretations, or suggestions, including those concerning my measurement regime, are appreciated. Chris

Clean the engine. I'm no flat-top expert, but I'm thinking what you think is oil is either: a) oil, but engine oil migrating through the grime or: gasoline going through the grime and becoming oily. I guess it could be carb oil, but I have a hard time imagining how such a shattered carb could even function. Chris

This amp is special. You see, it goes up to eleven. Normal amps only go up to ten. (With apologies to Reiner, et al.) I'm getting the impression that the 'R' status of the plug matters not a bit. I've been happy with NGK BPR6ES's, and with them I will stay. Unless they only have the BP6ES's available in which case, in they go. Put in a new set of plug wires today. Three words: Oh, yeah baby! Cleared up a couple of 'frog in the pan' problems as well. Thanks for the help. Certainly the immediate problem has been solved and I'll do a Sea-Foam with the next oil change. I'll be keeping a closer eye on the cap and rotor than I have in the past with an eye towards wobbly dizzy syndrome. Chris

I'll see if I can find the NGK spiral-wounds around town today. Let me see if I can ask this right: The reason for using inductive wires and resistive plugs is to eliminate, or at the least, greatly cutdown on radio interference. Among the responders to this post, there seems to be a fairly even split between 'R' and non-'R' plugs. I've always used inductive wires and 'R' plugs and don't have a trace of ignition noise through an unfiltered, good sounding, high output audio system. And yes, sound does matter to me very much. So, to finally get to the question(s). One more background: I do listen to AM. Not extensively, but critically for traffic reports on the "eights." Do the non-'R' plug users hear radio interference? Or if you did, were you able to eliminate it with simple filtering? Am I taking a performance hit using the 'R' plugs versus the non-'R' plugs? Finally, I'll look up the Sea-Foam procedure and put it in the book for the next oil change. Chris

Diseaszd, esmit208, Gary in NJ and FastWoman: What you are seeing, or not seeing in plug #2 is my lack of photography skills. The center electrode is there and undamaged. What you are seeing as missing or wire-thin is the shadow cast by the top of the electrode. You may be able to see what I'm talking about in the derezed posted pictures, but realistically, it would be a faith-based seeing. I assure you that I went out and triple-checked the plug and the electrode is OK. Much helpful to respond to, I'll just hit a couple: First, an appeal for mercy: My plugs aren't usually this bad! I posted up because they were so whacked I couldn't make sense of what was going on with them. Mr. Beck, I may be a short shifter, but a run to the grocery store a mile away usually puts 15 - 20 miles on the odometer. Slightly more seriously, I don't do the killer short trips in the Z. Any day that I fire up the Z, it gets thoroughly warmed up by running on the freeways or county highway that make an effective loop of the town, even if the destination is a mile from my house. No clouds of condensation follow me around for the first five miles because no moisture is left in the engine and exhaust when I return home and shut it down. FastWoman: I've used an oil flush twice (when purchased, and then a year or two ago). But, another couldn't hurt and I'll use Sea-Foam as you and so many others have recommended it. Today's adventures: Drove the Z into work. Twenty miles of back county road warm-up, then a modest twisty workout through a canyon followed by a a decent speed run over the Altamont through Coral Hollow. Couldn't go as fast as I would have liked, but California commuters, even in pickup trucks, even on ancient, narrow, car destruction to the left, death to the right mountain pass roads do set a surprisingly lively pace. Medium speed county highway cruise, one very short 25 mph city patch, then a growling blow out over the Sunol followed by a CHP-respecting 70 mph cruise the last 15 miles on the flats into San Jose. Many hours later, drove Z back home. A fairly quick trip because traffic was unaccountably light. Would have been quicker except for an abnormal number of absolute idiots out there. I'm gonna, "What the hell? It's like a Saturday out here." Really, it was like Costco had a sale on idiots. Let's say 170 miles total. I just wanted to make you jealous with the first part. Well, that wasn't the only reason. When I got home, I measured the resistance of the plug wires. Varied from 1800 ohms / foot (plug #5 -- heavy black) to 6950 ohms / foot (plug #4 -- light black) The wires to the whitish plugs (#2 and # 6) measured within 10% of 3000 ohms/ foot. What I found regarding whether these values were good, bad, or indifferent, indicated, depending on the source, that the wires were good, bad, or indifferent. And there didn't seem to be any correspondence with the plug conditions. Then I got the bright idea of measuring the coil to distributor wire: 3.4 Million ohms! I didn't bother measuring its length because the highest raw measure I got on the much longer plug cords was 19,000. That ain't right, right? The coil to distributor wire is made of the same stuff as the plug wires, isn't it? The printed identifier on the wire is exactly the same as on the plug wires, and I can't think of a good reason to use such a high resistance path between the coil and distributor. Now the reason I brought up the commute was that the Z started to feel a little flat the last 10 - 15 miles where the traffic flow, possibly because we finally got loose of the idiots, hit its customary 75 -- 85 and commenced dicing for position coming into and through the big swing. So I'm thinking, that while it wasn't hot today by any means, hung around 50 degrees the whole day, but doing 60 miles at a mile a minute, more or less, then a kickup to the 80s would cause some warming under hood. And while a little heat wouldn't have usually been enough to degrade performance, pushing a spark out through three and a half million ohms before even getting to the distributor had to be making the coil work really hard to generate not all that much power to the plugs. So, I'm thinking that while I may have some other problems, a good first step is to replace the ignition wires tomorrow. Oh, and the thermostat. Does this make sense? Or am I feeling the effects of something I haven't smoked in a very long time? Chris

I was thinking that the burn marks meant a lesser spark. But what you said is in more concordance with what I'm seeing. #2 and #6, physically next to each other getting a good spark while the others starve to a greater or lesser degree. I'm thinking this might take a couple of months to resolve. And while under some circumstances a "Wobbly Dizzy" sounds sorta fun, I'm thinking it will be a bit of a PIA in this context. Thanks all, I'll get back to you on the wires Tues/Wed/Thurs. Busy week ahead and I can spend _way_ too much time here reading posts on other topics. Chris

The #3 plug had a piece of crud where the spark normally jumps, I'm thinking it basically shorted out. I know its hard to tell from the pictures -- the desk puts a warm glow over the plugs, but when I tried white paper, the darker plugs disappeared into darkness. I think the #1 is the most normal looking -- tan insulator, not many deposits. Not an expert at this by any means. Up until this time, the plugs have been pretty consistent within each carb. And, he says with a small sense of accomplishment, increasingly consistent across the carbs. Except this time. The engine was idling rough, but didn't seem to miss once up to 800 rpm or so. Compression / Head Gasket? Could be. I haven't checked the compression since last summer when it was a trifle low, but consistent, across the cylinders. Ignition coil? Jeez, hope not. Replaced the stock one with an Accel during Summer of '09. I'm wondering if the change to the 195 thermostat has anything to do with this. I've always ran a 180, which consistently kept the gauge right in the middle. With the advent of winter -- not that wintery, but cooler, it dropped a pointer width. I thought I'd try a 195 to bring it up a bit. It does, too much, I think, because now it consistently runs two pointer widths hot. Also, an embarrassing thing to admit, but I'm a short shifter. Unless there is a need for tactical speed, I'll be in 4th by 35 mph, and sometimes go really crazy and drop it into 5th. Also, the proportion of in-town versus highway driving has been higher than usual for the last two months -- in fact about when I changed to the 195 thermostat. So, maybe the higher engine temp, combined with less high speed running (3000 rpm and over) is causing the carbon build-up (which is much worse than normal), and bad wires or a wobble in the distributor, or sloppy placement of the dizzy cap is causing the white plugs. That's whats so puzzling -- it wasn't running that bad, wasn't missing above idle, there doesn't seem to be an obvious richness difference between the carbs, the plugs have always been consistent or if not, could be traced to an obvious problem (fuel richness, dizzy cap wear, etc.) but there are three distinct plug sets -- the fouled, the suspiciously clean and the perhaps divinely protected normal one. I'll check the wires on Tuesday, probably switch back to a 180 termo then too and, well, drive and watch. Chris

I've used several types of plugs, but like you, have settled on the NGKs. I run the gap at .035 -- .038. Timing -- currently is at 17* BTDC _but_ I'm running it advanced because the vacumn advance has been nonfunctional since I bought the car. Checking the wires is a good idea, but at the moment (after changing plugs and cleaning up cap/rotor) its running pretty sharp so I don't know if a wire swap would tell me anything. I'll check with an ohmmeter and see if they come in around the same, allowing for the different runs to the plugs. I have a couple comments for FastWoman and I'll add a couple of my own thoughts to the end. Chris

Wasn't sure where to put this thread. Thought of Help Me! but its not an emergency. Electrical, probably, but that's only my best guess, so I thought I put it here under Engines as system. I have a 1972 240Z with stock intake system and a dizzy from an early 280ZX. The dizzy uses the E12-80 ignitor. MSA premium exhaust system, but stock exhaust manifold, installed last August. My idle has been a little rough lately and it felt a little down on power, but nothing major and its sometimes its just one's imagination. I pulled the plugs today and took some pictures of them. The plug numbering goes from left to right in each photo (1-3 and 4-6). My plugs are usually pretty consistent, at least within each bank (carb), but this time two really stood out, the #2 and #6 plugs. While the other plugs weren't exactly as I like to see them, I had never seen any quite like these. They weren't glazed like from overheating, just clean, I guess. While you can't see it in the photos, one of the other plugs had foul shorted with a chunk of something between the electrode and uh, the other electrode? Anode, I guess. I replaced the plugs with some cleaned up ones that I had removed early in their life back when I was getting a handle on adjusting the carbs and wanted to get a clean read. I pulled the dizzy cap, found the dirtiest looking contact, and sure enough it was the #2. The #6, though didn't seem much different than the rest. But they are physically next to each other. I took sandpaper to the contacts and the rotor, buttoned back up and took off for a test run. Felt much zippier. Don't think it was my imagination. And the idle was smoother. I richened the carbs up a week ago and installed a 195 thermostat maybe six weeks ago. I'm having a hard time coming up with a scenario as to how those changes would have only affected two plugs, one in each bank. But that's why I'm asking here. I bought the car a little less than three years ago, have put around 30,000 miles on it since. Can't remember if this is the second or third cap/rotor I've been through, but I do remember being surprised that the set immediately before this one had to be replaced. Does that make sense? The previous cap/rotor set didn't seem to last long. Is it a reasonable hypothesis to assume that the "white" plugs were caused by a weak or missing spark? If so, could it have been due to sloppiness on my part installing the rotor cap or symptomatic of a deeper problem, perhaps a warped shaft or worn bearings of some sort? Anything cheaper / simpler that could cause this that I've overlooked? Chris

Yoshi, I'm going to suggest that you are doing this backwards. If the engine is grimy enough, the actual location of an oil leak could be four feet away from where you spot the oil. With a clean engine spotting the source of an oil leak (or identifying just what the heck it is that is leaking) usually becomes a trivial problem. If you are worried about a fire, bare metal is pretty damn difficult to ignite, especially compared with a nice, rich hydrocarbon coating. Finally, figure how much time you spend wiping off gunked up tools, or parts, or searching for dropped nuts/bolts/washers that manage to stick to the side of the engine or suspension. Or not having to clean your driver's seat when a smear of grease travels without your knowledge from your arm to your leg to your butt. Quite seriously, the amount of time that it takes you to knock 95% of the crap out of the engine compartment will be saved back within 3 months by making repairs that much easier on yourself. Chris